Disposing of old hard drives

[courtg9000]

Have a mass clear at the Courtg9000 west midlands abode prior to quite a bit of renovation work.
I have come across a box of hard drives (20 or so - 2.5" and 3.5" @. Forgot I had them.
Now some of these will have some very sensitive information on them and some of it may or may not pertain to some very sensitive clients and systems.
Whats the best way to dispose of these please?
I was thinking of going ApeS*t with a hammer but is it best?
I would rather not have to pay an external supplier if possible.

[sadkingbilly]

Do you want to pass/sell them on for reuse/recycle, or just destroy them?
If the former, there are products that effectively 'wipe'* the data, but these are time consuming (real time, depending on access speeds).
Otherwise, smash them up with whatever. (put them under a steel sheet and drive over them a lot?).

*overwrite with binary '0' and/or '1' multiple times.

[courtg9000]

Do you want to pass/sell them on for reuse/recycle, or just destroy them?
If the former, there are products that effectively 'wipe'* the data, but these are time consuming (real time, depending on access speeds).
Otherwise, smash them up with whatever. (put them under a steel sheet and drive over them a lot?).

*overwrite with binary '0' and/or '1' multiple times.

Thanks for this. I don;t want to have to cable them up to a machine to run software if I can help it. I'm just destroying them.

[WTFH]

If you want to destroy them and have a bit of time on your hands, then take them apart. It's only the platters that need to be destroyed, so remove the casing and get the platters. Set them on top of a Laney LC50 Valve amp (or similar). After a few days they will be screwed. Next, separate the platters from each other and feed them through a goof office shredder.
Take the shredding and spilt them between 4 bags. Take one bag to your nearest tip. Put one bag in your household waste. Take the third bag and put it in a council bin in a different county to the one you are in. Put the 4th bag in your loft.

tl;dr: use a very strong magnet on the exposed platters, physically break the platters, do not dispose of them in one place.

[DoctorStrangelove]

Of course if you're a Septic Lunatic, you could try this:

I suspect a good sledge hammering would be as effective but probably quieter and less fun.

[b0redom]

Assuming it's commercial, rather than military, I'd just smash them with a hammer. When you can hear rattling inside the platters have broken. You'd have to be VERY dedicated to try and fix that.

[hobnob]

I would rather not have to pay an external supplier if possible.

The most secure method involves having the hard drive shredded, which isn't a DIY job. Depending on how long you're willing to spend on this, it might be better to pay someone else.

Most companies just say "Contact us for a quote", which is vague. I found one that mentioned specific prices:
Hard drive destruction services: what they do and how they protect your data
"You can expect to pay anything from £3 to £20 per hard drive."

[Dorkeaux]

I like taking them apart, salvaging the magnets for the fridge and the platters for coasters.

Some other good suggestions have been made, but the data on every hard disk is arranged by a chip on the PCB mounted on the drive.
It's not encrypted (very often, anyway) but the data will be practically impossible to recover without the board mounted on the drive.

The boards are very seldom interchangeable. Ask any specialist data recovery guys.

So if you are in a hurry, just smash and dispose of the circuit boards.
Not perfect, but probably secure enough.

Or roast them. Heat will derange the magnetic domains.

[woody1]

Got an incinerator bin? Get a roaring fire going with a few logs, and lob them in. All that will be left are a few bits of metal.

[NotAllThere]

Have you considered nuking the site from orbit?